How to compare multiple strings and assign values to the comparison?

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German Preciat Gonzalez 2016-6-28

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https://ww2.mathworks.cn/matlabcentral/answers/292630-how-to-compare-multiple-strings-and-assign-values-to-the-comparison

评论： José-Luis 2016-6-28

采纳的回答： José-Luis

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I have data from 6 different sources in a form of strings. I want to compare which strings are the same.

So if I have:

d1='111'
d2='223'
d3='111'
d4='125'
d5='111'
d6='125'

d1,d3,d5 are the same, d4 and d6 are the same too and d2 is different to all, so I will like to receive a vector where similar strings have the same number, like this:

[1 2 1 4 1 4]

if all the strings are different I will like to receive something like this:

[1 2 3 4 5 6]

or all the same

[1 1 1 1 1 1]

so far I've use a very ugly program with a lot of IF and ISEQUAL, any suggestions I will really appreciate it!

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Answer 1

José-Luis 2016-6-28

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编辑：José-Luis 2016-6-28

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Copying beginning from Siva because I'm lazy:

K = [{'111'} ; {'223'} ; {'111'} ; {'125'} ;{'111'} ; {'125'}] ;

Solving your problem more efficiently:

 [val,ia,ib] = unique(K,'stable') ; % get unique values
 your_answer = ia(ib);

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José-Luis 2016-6-28

My pleasure.

Guillaume 2016-6-28

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I find that method of creating a cell array very odd!

K = {'111'; '223'; '111'; '125'; '111'; '125'};

is less to type and a lot simpler.

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Answer 2

Guillaume 2016-6-28

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Dr. Siva Srinivas Kolukula has the right idea: use unique. His answer is unnecessarily complicated though.

First though, do not use numbered variables. If they're numbered it means that they've got some sort of relationship. That relationship is much better expressed by putting the content of these variables together into the same container: matrix, cell array, map, table, etc. In your case, a cell array seems best.

Anyway, the third return value of unique is what you're after:

d = {'111', '223', '111', '125', '111', '125'}
[~, ~, uid] = unique(d, 'stable')  %'stable' is optional. If not present unique ids are assigned alphabetically

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Guillaume 2016-6-28

Well, the question was "I will like to receive a vector where similar strings have the same number", which the above does.

José-Luis 2016-6-28

Indeed, but that's not what the example result showed. Anyway, interpreting questions is an art sometimes...

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Answer 3

KSSV 2016-6-28

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编辑：KSSV 2016-6-28

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clc; clear all ;
K = [{'111'} ; {'223'} ; {'111'} ; {'125'} ;{'111'} ; {'125'}] ;
[val,idx] = unique(K,'stable') ; % get unique values
iwant = zeros(size(K)) ;  % initialize what you want 
count = 0 ;    
% loop for each equal string 
for i = 1:length(idx)
    count = count+1 ;
    Index = strfind(K,val{i}) ;
    Index = find(not(cellfun('isempty', Index))) ;
    iwant(Index) = count ;
end